Greg Koltun
Greg is an Emeritus Hydrologist and surface-water specialist for the Ohio-Kentucky-Indiana Water Science Center.
He received a B.S. in microbiology and an M.S. in civil engineering from the Ohio State University and has worked on a wide array of research, including topics in hydrology, hydraulics, water quality, water use, modeling, and applied statistics. Greg teaches a USGS national training course on sediment and chemical loading computation methods and was an adjunct professor at the Ohio State University where he taught applied hydrology.
Science and Products
Grand River near Painesville, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Huron River near Milan, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Black River at Elyria, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Cuyahoga River at Independence, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Phosphorus, nitrogen, chloride, and suspended-sediment load estimates for the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2023 Phosphorus, nitrogen, chloride, and suspended-sediment load estimates for the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2023
Phosphorus, nitrogen, chloride, and suspended-sediment loads, in 24 U.S. tributaries of the Great Lakes, were estimated using U.S. Geological Survey (USGS) data from the Great Lakes Restoration Initiative (GLRI) monitoring program for the period Oct 2010 through Sept 2023 (USGS water years 2011-23). Specific water-quality constituents include total phosphorus, orthophosphate, particulate
Pesticide, organic wastewater compound (OWC) and polycyclic aromatic hydrocarbon (PAH) data determined from samples collected with instream passive samplers in the Big Darby Creek Basin, Ohio, 2020-21 Pesticide, organic wastewater compound (OWC) and polycyclic aromatic hydrocarbon (PAH) data determined from samples collected with instream passive samplers in the Big Darby Creek Basin, Ohio, 2020-21
This dataset contains estimated time-weighted average water concentrations and quality control samples for pesticide, organic wastewater compound (OWC) and polycyclic aromatic hydrocarbon (PAH) data determined from samples collected with instream passive samplers in the Big Darby Creek Basin, Ohio, 2020-21.
Supporting data for low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020 (ver. 1.1, October 2024) Supporting data for low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020 (ver. 1.1, October 2024)
This data release comprises the tabular data used to develop regression equations for estimating selected low-flow statistics for ungaged streams in Ohio that are not substantially affected by regulation, diversions, or other anthropogenic influences, and the geographic information systems (GIS) layer to implement them in the U.S. Geological Survey StreamStats application (https:/...
Annual streamflow statistics for selected streamgages in and near the shale play area of eastern Ohio (through water year 2021) Annual streamflow statistics for selected streamgages in and near the shale play area of eastern Ohio (through water year 2021)
This data release includes datasets with annual streamflow statistics determined with the Indicators of Hydrologic Alteration software and R source code to create time-series plots with overlaid locally weighted scatterplot smoothing (lowess) lines.
Phosphorus, nitrogen, and suspended-sediment loads measured at the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2020 Phosphorus, nitrogen, and suspended-sediment loads measured at the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2020
Phosphorus, nitrogen, and suspended-sediment loads, in 24 U.S. tributaries of the Great Lakes, were calculated using U.S. Geological Survey (USGS) data from the Great Lakes Restoration Initiative (GLRI) monitoring program for the period Oct 2010 through Sept 2020 (USGS water years 2011–2020). Total phosphorus, orthophosphate, particulate phosphorus, total nitrogen, nitrate plus nitrite...
Model data archive—Trends in Selected Environmental, Anthropogenic, and Water-Quality Characteristics in the Upper White River Basin, Indiana, 1991–2020 Model data archive—Trends in Selected Environmental, Anthropogenic, and Water-Quality Characteristics in the Upper White River Basin, Indiana, 1991–2020
This archive contains input files used in regression analyses to estimate concentrations and flux of total phosphorus, nitrate plus nitrite, total Kjeldahl nitrogen, and total suspended solids at selected locations on the Upper White River and output files containing annual estimates of flux and mean daily concentrations.of those same constituents, along with their 90 percent prediction...
Filter Total Items: 53
Changes in phosphorus concentration and flux from 2011 to 2023 in major U.S. tributaries to the Laurentian Great Lakes Changes in phosphorus concentration and flux from 2011 to 2023 in major U.S. tributaries to the Laurentian Great Lakes
Reducing phosphorus (P) flux to the Great Lakes is critical for improving water quality and controlling eutrophication. We used 13 water years (2011–2023) of U.S. Geological Survey data from 24 major U.S. tributaries (representing 47% of the U.S. Great Lakes watershed area) to evaluate temporal changes in orthophosphate (PO4-P) and total P (TP) using Weighted Regressions on Time...
Authors
Dustin William Kincaid, Matthew W. Diebel, Erin E. Bertke, Donald B. Bonville, G. F. Koltun, Dale M. Robertson, Luke C. Loken
Potential water-quality and hydrology stressors on freshwater mussels with development of environmental DNA assays for selected mussels and macroinvertebrates in Big Darby Creek Basin, Ohio, 2020–22 Potential water-quality and hydrology stressors on freshwater mussels with development of environmental DNA assays for selected mussels and macroinvertebrates in Big Darby Creek Basin, Ohio, 2020–22
The richness and abundance of freshwater mussels in the Big Darby Creek Basin has declined in recent decades, according to survey results published by the Ohio Biological Survey. In October 2016, a major mussel die-off of undetermined cause reportedly affected over 50 miles of Big Darby Creek; however, fishes and other wildlife were not noticeably impacted. Pollution, habitat destruction...
Authors
Carrie A. Huitger, G. F. Koltun, Erin A. Stelzer, Lauren D. Lynch
Low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020 Low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020
A study was conducted by the U.S. Geological Survey, in cooperation with the Ohio Water Development Authority and the Ohio Environmental Protection Agency, to compute low-flow frequency, flow-duration, and harmonic mean flow statistics for long-term streamflow gages and to develop regression equations to estimate those statistics at unregulated, ungaged stream locations in Ohio. The flow
Authors
Branden L. VonIns, G. F. Koltun
Analysis of water use associated with hydraulic fracturing and determination of baseline water quality in watersheds within the shale play of eastern Ohio, 2021–23 Analysis of water use associated with hydraulic fracturing and determination of baseline water quality in watersheds within the shale play of eastern Ohio, 2021–23
The U.S. Geological Survey, in cooperation with the Ohio Department of Natural Resources, performed a two-part study to (1) assess water use and temporal trends and changes in streamflow, and to (2) characterize 2021–23 baseline water quality, as they relate to oil and gas extraction activities in selected eastern Ohio watersheds. Between calendar years 2010 and 2019, hydraulic...
Authors
S. Alex Covert, G. F. Koltun
Potential drivers of change in fluxes of nutrients and total suspended solids in the upper White River Basin, Indiana, Water Years 1997–2019 Potential drivers of change in fluxes of nutrients and total suspended solids in the upper White River Basin, Indiana, Water Years 1997–2019
The U.S. Geological Survey and The Nature Conservancy previously collaborated to evaluate changes and trends in the concentrations and flux of nutrients (total phosphorus, as phosphorus; nitrate plus nitrite, as nitrogen; and total Kjeldahl nitrogen, as nitrogen) and total suspended solids (TSS) at three study gages located on the upper White River at Muncie, near Nora, and near...
Authors
G. F. Koltun, Cassie Hauswald
Trends in environmental, anthropogenic, and water-quality characteristics in the upper White River Basin, Indiana Trends in environmental, anthropogenic, and water-quality characteristics in the upper White River Basin, Indiana
The U.S. Geological Survey (USGS), in cooperation with The Nature Conservancy, undertook a study to update and extend results from a previous study (Koltun, 2019, https://doi.org/10.3133/sir20195119), using data from 3 additional years and newer estimation methods. Koltun (2019) assessed trends in streamflow, precipitation, and estimated annual mean concentrations and flux of nitrate...
Authors
G. F. Koltun
Culvert Analysis Program (CAP) version 2021.0.0 Culvert Analysis Program (CAP) version 2021.0.0
The culvert analysis program (CAP) version 2021 updates and corrects know errors in standalone versions 98-07c or earlier and iRIC version 3.X or earlier.
GCLAS (Graphical Constituent Loading Analysis System): A tool for computing loads of constituents transported in rivers GCLAS (Graphical Constituent Loading Analysis System): A tool for computing loads of constituents transported in rivers
GCLAS is a program designed to compute daily and annual loadings of constituents transported in rivers.
Science and Products
Grand River near Painesville, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Huron River near Milan, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Black River at Elyria, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Cuyahoga River at Independence, OH
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Ohio, Kentucky, and Indiana. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS...
Phosphorus, nitrogen, chloride, and suspended-sediment load estimates for the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2023 Phosphorus, nitrogen, chloride, and suspended-sediment load estimates for the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2023
Phosphorus, nitrogen, chloride, and suspended-sediment loads, in 24 U.S. tributaries of the Great Lakes, were estimated using U.S. Geological Survey (USGS) data from the Great Lakes Restoration Initiative (GLRI) monitoring program for the period Oct 2010 through Sept 2023 (USGS water years 2011-23). Specific water-quality constituents include total phosphorus, orthophosphate, particulate
Pesticide, organic wastewater compound (OWC) and polycyclic aromatic hydrocarbon (PAH) data determined from samples collected with instream passive samplers in the Big Darby Creek Basin, Ohio, 2020-21 Pesticide, organic wastewater compound (OWC) and polycyclic aromatic hydrocarbon (PAH) data determined from samples collected with instream passive samplers in the Big Darby Creek Basin, Ohio, 2020-21
This dataset contains estimated time-weighted average water concentrations and quality control samples for pesticide, organic wastewater compound (OWC) and polycyclic aromatic hydrocarbon (PAH) data determined from samples collected with instream passive samplers in the Big Darby Creek Basin, Ohio, 2020-21.
Supporting data for low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020 (ver. 1.1, October 2024) Supporting data for low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020 (ver. 1.1, October 2024)
This data release comprises the tabular data used to develop regression equations for estimating selected low-flow statistics for ungaged streams in Ohio that are not substantially affected by regulation, diversions, or other anthropogenic influences, and the geographic information systems (GIS) layer to implement them in the U.S. Geological Survey StreamStats application (https:/...
Annual streamflow statistics for selected streamgages in and near the shale play area of eastern Ohio (through water year 2021) Annual streamflow statistics for selected streamgages in and near the shale play area of eastern Ohio (through water year 2021)
This data release includes datasets with annual streamflow statistics determined with the Indicators of Hydrologic Alteration software and R source code to create time-series plots with overlaid locally weighted scatterplot smoothing (lowess) lines.
Phosphorus, nitrogen, and suspended-sediment loads measured at the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2020 Phosphorus, nitrogen, and suspended-sediment loads measured at the Great Lakes Restoration Initiative tributary monitoring network: Water years 2011–2020
Phosphorus, nitrogen, and suspended-sediment loads, in 24 U.S. tributaries of the Great Lakes, were calculated using U.S. Geological Survey (USGS) data from the Great Lakes Restoration Initiative (GLRI) monitoring program for the period Oct 2010 through Sept 2020 (USGS water years 2011–2020). Total phosphorus, orthophosphate, particulate phosphorus, total nitrogen, nitrate plus nitrite...
Model data archive—Trends in Selected Environmental, Anthropogenic, and Water-Quality Characteristics in the Upper White River Basin, Indiana, 1991–2020 Model data archive—Trends in Selected Environmental, Anthropogenic, and Water-Quality Characteristics in the Upper White River Basin, Indiana, 1991–2020
This archive contains input files used in regression analyses to estimate concentrations and flux of total phosphorus, nitrate plus nitrite, total Kjeldahl nitrogen, and total suspended solids at selected locations on the Upper White River and output files containing annual estimates of flux and mean daily concentrations.of those same constituents, along with their 90 percent prediction...
Filter Total Items: 53
Changes in phosphorus concentration and flux from 2011 to 2023 in major U.S. tributaries to the Laurentian Great Lakes Changes in phosphorus concentration and flux from 2011 to 2023 in major U.S. tributaries to the Laurentian Great Lakes
Reducing phosphorus (P) flux to the Great Lakes is critical for improving water quality and controlling eutrophication. We used 13 water years (2011–2023) of U.S. Geological Survey data from 24 major U.S. tributaries (representing 47% of the U.S. Great Lakes watershed area) to evaluate temporal changes in orthophosphate (PO4-P) and total P (TP) using Weighted Regressions on Time...
Authors
Dustin William Kincaid, Matthew W. Diebel, Erin E. Bertke, Donald B. Bonville, G. F. Koltun, Dale M. Robertson, Luke C. Loken
Potential water-quality and hydrology stressors on freshwater mussels with development of environmental DNA assays for selected mussels and macroinvertebrates in Big Darby Creek Basin, Ohio, 2020–22 Potential water-quality and hydrology stressors on freshwater mussels with development of environmental DNA assays for selected mussels and macroinvertebrates in Big Darby Creek Basin, Ohio, 2020–22
The richness and abundance of freshwater mussels in the Big Darby Creek Basin has declined in recent decades, according to survey results published by the Ohio Biological Survey. In October 2016, a major mussel die-off of undetermined cause reportedly affected over 50 miles of Big Darby Creek; however, fishes and other wildlife were not noticeably impacted. Pollution, habitat destruction...
Authors
Carrie A. Huitger, G. F. Koltun, Erin A. Stelzer, Lauren D. Lynch
Low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020 Low-flow statistics computed for streamflow gages and methods for estimating selected low-flow statistics for ungaged stream locations in Ohio, water years 1975–2020
A study was conducted by the U.S. Geological Survey, in cooperation with the Ohio Water Development Authority and the Ohio Environmental Protection Agency, to compute low-flow frequency, flow-duration, and harmonic mean flow statistics for long-term streamflow gages and to develop regression equations to estimate those statistics at unregulated, ungaged stream locations in Ohio. The flow
Authors
Branden L. VonIns, G. F. Koltun
Analysis of water use associated with hydraulic fracturing and determination of baseline water quality in watersheds within the shale play of eastern Ohio, 2021–23 Analysis of water use associated with hydraulic fracturing and determination of baseline water quality in watersheds within the shale play of eastern Ohio, 2021–23
The U.S. Geological Survey, in cooperation with the Ohio Department of Natural Resources, performed a two-part study to (1) assess water use and temporal trends and changes in streamflow, and to (2) characterize 2021–23 baseline water quality, as they relate to oil and gas extraction activities in selected eastern Ohio watersheds. Between calendar years 2010 and 2019, hydraulic...
Authors
S. Alex Covert, G. F. Koltun
Potential drivers of change in fluxes of nutrients and total suspended solids in the upper White River Basin, Indiana, Water Years 1997–2019 Potential drivers of change in fluxes of nutrients and total suspended solids in the upper White River Basin, Indiana, Water Years 1997–2019
The U.S. Geological Survey and The Nature Conservancy previously collaborated to evaluate changes and trends in the concentrations and flux of nutrients (total phosphorus, as phosphorus; nitrate plus nitrite, as nitrogen; and total Kjeldahl nitrogen, as nitrogen) and total suspended solids (TSS) at three study gages located on the upper White River at Muncie, near Nora, and near...
Authors
G. F. Koltun, Cassie Hauswald
Trends in environmental, anthropogenic, and water-quality characteristics in the upper White River Basin, Indiana Trends in environmental, anthropogenic, and water-quality characteristics in the upper White River Basin, Indiana
The U.S. Geological Survey (USGS), in cooperation with The Nature Conservancy, undertook a study to update and extend results from a previous study (Koltun, 2019, https://doi.org/10.3133/sir20195119), using data from 3 additional years and newer estimation methods. Koltun (2019) assessed trends in streamflow, precipitation, and estimated annual mean concentrations and flux of nitrate...
Authors
G. F. Koltun
Culvert Analysis Program (CAP) version 2021.0.0 Culvert Analysis Program (CAP) version 2021.0.0
The culvert analysis program (CAP) version 2021 updates and corrects know errors in standalone versions 98-07c or earlier and iRIC version 3.X or earlier.
GCLAS (Graphical Constituent Loading Analysis System): A tool for computing loads of constituents transported in rivers GCLAS (Graphical Constituent Loading Analysis System): A tool for computing loads of constituents transported in rivers
GCLAS is a program designed to compute daily and annual loadings of constituents transported in rivers.